KR20210072761A - electrosurgical instruments - Google Patents

Abstract

In one aspect, the present invention provides an electrosurgical instrument for performing hemostasis by radiating microwave energy from a distal end, wherein the conductive radiation electrode is coated with an insulating non-stick material. In another aspect, the present invention provides an electrosurgical instrument for performing hemostasis using radio frequency or microwave electromagnetic energy, wherein one distal end of the instrument is for delivering a fluid to or from a treatment site. a conductive hollow needle, wherein the hollow needle is electrically grounded.

Description

electrosurgical instruments

The present invention relates to an electrosurgical instrument for delivering microwave energy and/or radio frequency energy to a biological tissue to ablate a target tissue. The electrosurgical instrument includes a fluid delivery channel coupled to the needle for delivering fluid to a treatment site. The probe may be inserted through a catheter or channel of an endoscope, or used for laparoscopic or open surgery.

Electromagnetic (EM) energy, and in particular microwave and radio frequency (RF) energy, has been found useful in electrosurgery for its ability to cut, coagulate and ablate body tissue. Generally, an apparatus for delivering EM energy to body tissue includes a generator comprising a source of EM energy and an electrosurgical instrument coupled to the generator for delivering energy to the tissue. Conventional electrosurgical instruments are often designed to be inserted percutaneously into a patient's body. However, transdermal placement of the device within the body can be difficult, for example, when the target site is within a moving lung or a thin walled portion of the gastrointestinal (GI) tract. Other electrosurgical instruments may be delivered to the target site by means of a surgical examination device (eg, an endoscope) that may be disposed through a channel within the body, such as the lumen of the colon or esophagus or the airway. This enables minimally invasive treatment, which can reduce patient mortality and reduce intraoperative and postoperative complications.

Tissue ablation using microwave EM energy relies on the fact that biological tissue is mainly composed of water. Human soft organ tissue generally has a water content between 70% and 80%. Water molecules have a permanent electric dipole moment, meaning that there is a charge imbalance across the molecule. This charge imbalance causes the molecule to move in response to the force generated by the provision of a time-varying electric field as the molecule rotates to align its electric dipole moment with the polarity of the provided field. Due to the fast molecular vibrations at microwave frequencies, frictional heating is caused, which in turn dissipates the field energy in the form of heat. This is known as dielectric heating.

This principle is utilized in microwave ablation therapy, where water molecules in the target tissue are rapidly heated by providing a local electromagnetic field at microwave frequencies, thereby causing tissue coagulation and cell death. Methods of using microwave emission probes to treat various conditions of the lungs and other organs are also known. For example, in the lungs, microwave radiation can be used to treat asthma and to excise tumors or lesions.

RF EM energy may be used for cutting and/or coagulation of biological tissue. The method of cutting using RF energy is based on the principle that when an electric current passes through a tissue matrix (supported by the ionic content of the cells, i.e. sodium and potassium), the impedance to the flow of electrons across the tissue creates heat. It works. When a pure sine wave is provided to the tissue matrix, sufficient heat is generated within the cells to evaporate the water contained in the tissue. Accordingly, the internal pressure of the cell is significantly increased, which cannot be controlled by the cell membrane and causes the cell to rupture. When this phenomenon occurs in a wide area, it can be seen that the tissue is ruptured.

RF coagulation works by providing the tissue with a less efficient waveform instead of evaporating, in which the cell contents are heated to about 65°C. It dries the tissue by drying and denatures the collagen that forms the cell wall and the proteins in the vessel wall. Protein denaturation acts as a stimulus to the coagulation cascade, resulting in increased mass. At the same time, collagen in the cell wall is denatured from rod-shaped molecules into coils, thereby constricting blood vessels and reducing their size, and providing a lump at the anchoring point, reducing the area to be plugged.

Some electrosurgical instruments may be used with a fluid delivery system to deliver a fluid (eg, liquid and/or gas) to a treatment site. In some cases, a fluid delivery system can be used to administer a liquid drug to a treatment site. For example, it is known to administer adrenaline to the site of bleeding to constrict blood vessels during heavy bleeding.

As another example, a fluid delivery system may be used to deliver argon gas to a treatment site to perform argon plasma coagulation (APC). APC is a surgical technique that controls bleeding in a manner that does not require physical contact between the electrosurgical instrument and the target tissue. In APC, an argon jet is ionized with microwave and/or RF energy delivered by an electrosurgical instrument to control coagulation and bleeding.

The disclosure herein refers to two aspects that may be provided together or separately.

In a first aspect, the present invention provides an electrosurgical instrument for performing hemostasis by radiating microwave energy from a distal end, wherein a conductive electrode from which microwave energy is radiated is coated with an insulating non-stick material.

In a second aspect, the present invention provides an electrosurgical instrument for performing hemostasis using radio frequency (RF) or microwave electromagnetic (EM) energy, wherein one distal end of the instrument delivers a fluid to or from a treatment site and a conductive hollow needle for transferring fluid from the hollow needle to electrically grounded.

For the first aspect, the inventors have found that tissue tends to stick to the instrument tip when coagulated or resected. This can result in tissue damage or bleeding when the instrument tip is removed from the treatment site. Providing a non-stick coating to at least the conductive element (eg, electrode) that emits microwave energy can prevent tissue from sticking to the instrument tip. In some instances, the entire instrument tip may be coated. Providing a non-stick coating allows for easy removal of the instrument tip from the treatment site after application of microwave energy. The non-stick coating may be composed of a biocompatible material such as Parylene C or Parylene D.

The inventors have realized that hemostasis can be performed effectively using radiated microwave energy. When microwave energy is used, the non-stick coating may be insulating (ie, non-conductive) because the microwave energy is radiated from the radiating structure. Various insulating biocompatible non-stick materials are known and can be used for this purpose. Conversely, hemostasis is usually performed using RF energy. In this case, an insulating non-stick coating cannot be used as the electrode must be exposed so that the RF current flows into the target tissue. The inventors are not aware of any suitable material that is biocompatible, conductive and non-stick that can be used to provide a non-stick coating for a device that performs hemostasis by energy transfer by conduction. Therefore, performing hemostasis with radiated microwave energy can coat the instrument tip with an insulating non-stick material, thereby preventing tissue from sticking to the instrument tip and facilitating the use of the instrument.

In a second aspect, the inventors have discovered that a hollow needle can interfere with microwave and/or RF energy emitted by an electrosurgical instrument when it is not grounded (eg, left floating). The present inventors have found that the interference effect due to the non-grounded hollow needle is particularly pronounced at microwave energy. This may distort the radiation profile of the electrosurgical instrument and/or reduce the efficiency with which EM energy is delivered to the target tissue.

The inventors have discovered that the interference of the hollow needle with microwave and/or RF energy emitted by an electrosurgical instrument can be reduced by grounding the hollow needle. This may serve to improve the shape of the radial profile of the electrosurgical instrument, for example, by preventing the needle from extending too far in front of the distal end when extended. This may improve the efficiency of delivery of EM energy to the target tissue, for example, by allowing the delivered energy to be confined in the immediate vicinity of the distal end. As a result, the control of EM energy delivery to the target tissue can be improved.

According to a first aspect, an electrosurgical instrument may be provided, the electrosurgical instrument comprising a coaxial supply cable for transmitting microwave energy, the coaxial supply cable comprising an inner conductor, an outer conductor and an inner conductor and an outer conductor having a dielectric material that separates; an instrument end disposed at a distal end of the coaxial supply cable for receiving microwave energy and/or radio frequency energy; and a fluid channel for delivering a fluid to an instrument tip, the instrument tip comprising: a radiating structure for radiating microwave energy into the biological tissue; and a hollow needle in fluid communication with the fluid channel, wherein the hollow needle is arranged to deliver fluid from the fluid channel to the treatment site, and wherein the radiating structure is coated with an insulating non-stick material.

An insulating non-stick material may be provided as a coating on all or a portion of the instrument tip. For example, the instrument tip may be coated with an insulating non-stick material or the coating may be limited to a radiating structure.

The coating of insulating non-tacky material may have a thickness of 40 μm or less, such as in the range of 1-40 μm. Preferably, the thickness is in the range of 10 μm or less, eg 3-4 μm. The thickness of the insulating material may vary depending on the insulating end. It may have a thin portion disposed over the radiating structure.

The insulating non-stick material may be biocompatible. In some embodiments, the non-stick material is Parylene C or Parylene D.

According to a second aspect, an electrosurgical instrument may be provided, the electrosurgical instrument comprising a coaxial supply cable for transmitting microwave energy and/or high frequency energy, the coaxial supply cable comprising an inner conductor, an outer conductor and an inner conductor having a dielectric material separating the conductor and the outer conductor; an instrument end disposed at a distal end of the coaxial supply cable for receiving microwave energy and/or radio frequency energy; and a fluidic channel for delivering a fluid to a tip of the device, the tip comprising: an energy delivery structure for delivering microwave energy and/or radio frequency energy to a biological tissue; and a hollow needle in fluid communication with the fluid channel, wherein the energy transfer structure includes a radiating structure for radiating microwave energy into the biological tissue, wherein the hollow needle is electrically connected to an external conductor to ground the hollow needle.

The first and second aspects may be combined, for example, to provide an electrosurgical instrument having a grounded needle and an insulating non-stick coating. Additional optional features applicable to both aspects are described below.

The device may be operable to coagulate and/or ablate target tissue within the body. For example, the device may be used to treat tissue of the lungs or gastrointestinal tract, but may also be used to treat tissue of other organs (eg, the uterus). To effectively treat the target tissue, the instrument tip should be positioned as close as possible to (in most cases, inside) the target tissue. In order to reach a target tissue (eg, lung), the device may have to be guided around an obstruction through a passageway (eg, an airway). This means that the instrument will ideally have as little cross-section as possible and as flexible as possible. In particular, the device must be very flexible near the tip, so it may be necessary to maneuver it along narrow passages such as bronchioles that are narrow and bendable.

The coaxial supply cable may be a conventional low loss coaxial cable that may be connected to an electrosurgical generator at one end. In particular, the inner conductor may be an elongated conductor extending along the longitudinal axis of the coaxial supply cable. A dielectric material may be disposed around the inner conductor, eg, the first dielectric material may have a channel through which the inner conductor extends. The outer conductor may be a sleeve made of a conductive material disposed on the surface of the dielectric material. The coaxial supply cable may further include an external protective sheath to insulate and protect the cable. In some instances, the protective sheath may be made of or coated with a non-stick material to prevent tissue from sticking to the cable.

A fluid channel may be provided to deliver a fluid (eg, liquid or gas) from the proximal end of the electrosurgical instrument to the instrument end. The fluid channel may be connected to a fluid source at its proximal end. For example, a fluidic channel may be used to deliver a liquid drug (eg, adrenaline) to an instrument tip. When performing APC using an electrosurgical instrument, a fluid channel may be used to deliver argon gas to the instrument tip. The fluid channel may also be used to transport fluid from the instrument tip to the proximal end of the electrosurgical instrument. For example, fluid present at the treatment site around the instrument tip may be drawn through the hollow needle and expelled through the fluid channel to expel the fluid from the treatment site. The fluid channel can include, for example, a flexible tube (lumen) extending along the length of the electrosurgical instrument, eg, extending from the proximal end of the electrosurgical instrument to the instrument end.

In some examples, the fluid channel may be arranged along a coaxial supply cable. The fluid channel and the coaxial supply cable may be received within a flexible instrument sleeve, and the instrument sleeve may form a lumen carrying the coaxial supply cable and the fluid channel. The instrument sleeve may be made of or coated with a non-stick material (eg, PTFE) to prevent tissue sticking. An insert may be provided in the instrument sleeve to maintain the position of the fluid channel and coaxial supply cable within the instrument sleeve. Alternatively, the instrument sleeve may be a multi-lumen tube such that a coaxial supply cable is received within a first lumen of the instrument sleeve and a fluid channel is received within a second lumen of the instrument sleeve.

In some examples, the fluid channel may be received within a coaxial supply cable. For example, the dielectric material in the coaxial supply cable may include a lumen from which the fluid channel extends. In another example, the inner conductor may be a hollow conductor, eg, the inner conductor may be formed by a tube of conductive material. In this case, the fluid channel may be provided in the hollow inner conductor. Receiving the fluid channel within the coaxial supply cable may serve to reduce the outer diameter of the electrosurgical instrument.

An instrument tip is located at the distal end of the coaxial feed cable and is provided to deliver EM energy transported along the coaxial feed cable to the target tissue. The instrument tip is also provided for delivering fluid from the fluid channel to the treatment site. The fluid channel may terminate near the distal end of the coaxial supply channel, eg, in front of the instrument tip. Alternatively, a portion of the fluid channel may extend to the instrument tip. The instrument end may be permanently or removably attached to the coaxial supply cable and fluid channel.

The energy transmitting structure is arranged to transmit microwave and/or RF energy delivered by the coaxial supply cable. The radiating structure is electrically connected to the coaxial supply cable to receive the microwave energy. The radiating structure may be configured with microwave energy having a predetermined energy such that the instrument produces a desired radiation profile and/or type of treatment (eg, tissue ablation, cutting or coagulation). For example, the radiating structure may consist of a monopolar microwave antenna, eg, the radiating structure may include an elongated conductor coupled to an inner conductor and arranged to radiate microwave energy along its length. Alternatively, the radiating structure may consist of a bipolar microwave antenna, eg, the radiating structure may include a pair of electrodes each connected to an inner conductor and an outer conductor and arranged to radiate microwave energy.

When the energy transmitting structure is configured to transmit RF energy, the energy transmitting structure may include a pair of RF electrodes each connected to an inner conductor and an outer conductor. A pair of RF electrodes may function as an active electrode and a return electrode, and tissue located in a region between the electrodes is ablated or coagulated by the RF energy.

When an electrosurgical instrument is used to perform APC, the energy transfer construct may include a pair of electrodes disposed near the hollow needle for igniting and maintaining a plasma from argon gas using microwave and/or RF energy. can

In some cases, the energy transfer structure may be configured to deliver microwave and RF energy simultaneously or sequentially. For example, if the energy transfer structure includes a pair of electrodes, the pair of electrodes may function as active and return electrodes at RF frequencies and as bipolar antennas at microwave frequencies.

A hollow needle is provided to deliver fluid from a fluid channel to a treatment site. The treatment site may include a region of target biological tissue located proximate to (eg, in front of) the tip of the device. The hollow needle may be formed of a tube of a certain length. The hollow needle may be made of a conductive material (eg, metal). The hollow needle may have one proximal end in fluid communication with the fluid channel, and fluid from the fluid channel may be delivered to the hollow needle. For example, the proximal end of the hollow needle may be located inside the distal portion of the fluid channel. To prevent fluid leakage at the joint between the fluid channel and the hollow needle, a seal may be formed between the hollow needle and the fluid channel. The hollow needle may have a distal end having an opening through which fluid may be dispensed to the treatment site. Fluid may be aspirated with a needle through an opening in the distal end to expel fluid from the treatment site. The distal end of the hollow needle may be sharp (eg, may be pointed) to facilitate insertion of the hollow needle into tissue. For example, the hollow needle may be a hypodermic needle.

The hollow needle is electrically connected to the outer conductor of the coaxial supply cable. This serves to ground the hollow needle to the outer conductor. In general, the outer conductor of the coaxial supply cable may be connected to an electrical ground (eg 0V), and both the outer conductor and the hollow needle may be grounded. The hollow needle may be electrically connected to the external conductor using any suitable means. For example, a conductive wire or other conductor may be connected between the outer conductor and the hollow needle.

Because the hollow needle is electrically connected to the external conductor, the hollow needle is not at a floating voltage with respect to the coaxial supply cable. The electrical connection between the hollow needle and the outer conductor may also reduce any floating capacitance between the outer conductor and the hollow needle. As a result, the interference effect by the hollow needle on the EM energy transfer by the energy transfer structure can be reduced. This may be particularly advantageous for the delivery of microwave energy, as the inventors found that the interference effect caused by the hollow needle may be more pronounced at microwave frequencies. Reducing the interference effect of the hollow needle can improve the efficiency of EM energy delivery to the target tissue as well as improve the radiation profile of the instrument tip (eg, by reducing distortion due to interference). Also, if the hollow needle is grounded to an external conductor, the safety of the electrosurgical instrument can be improved because it can prevent a large voltage from being generated between the hollow needle and the energy transfer structure.

In some embodiments, the instrument tip may include a grounding element arranged to electrically connect the hollow needle to an external conductor. Thus, the electrical connection between the outer conductor and the hollow needle can be located at the instrument tip itself. The grounding element may electrically connect the hollow needle to a distal portion of the outer conductor. In some cases, the distal portion of the outer conductor may extend to the instrument tip. The grounding element may comprise a piece of conductive material that electrically connects the hollow conductor to the outer conductor. The grounding element may be connected to the external conductor and the hollow needle by any suitable means, for example by mechanical connection, conductive adhesive (eg, epoxy) or soldering or welding bonding. By providing a grounding element directly at the instrument tip, the length of the electrical path between the hollow needle and the outer conductor can be reduced. This can ensure a good electrical connection between the hollow needle and the outer conductor and facilitate the formation of the electrical connection.

In some embodiments, the grounding element can include a body having a first connecting surface and a second connecting surface arranged to hold a hollow needle and an outer conductor, respectively. The first connection surface and the second connection surface may be electrically connected together, such as, for example, different surface regions of a common conductive body. The hollow needle may be electrically connected to the first connection surface. The external conductor may be electrically connected to the second connection surface. Since both the hollow needle and the outer conductor are connected to a surface on the body of the grounding element, the grounding element may be provided to secure one position of the hollow needle with respect to the outer conductor (and thus the coaxial supply cable). Thus, the grounding element may provide the dual function of electrically connecting the hollow needle to the outer conductor and securing the hollow needle and the outer conductor in place relative to each other. This may serve to improve the integrity of the instrument tip. The body of the grounding element may be a single component made of a conductive material (eg metal), in which case the hollow needle and the outer conductor are electrically connected by the body of the grounding element. Alternatively, the body may be made of an insulating material, and the first and second connecting surfaces may be formed by a conductive layer provided on the surface of the body. An electrical path between the first and second connecting surfaces may then be provided on or in the body.

The hollow needle may be electrically connected to the first connection surface using any suitable means. In one example, the hollow needle may be secured against the first connecting surface to form electrical contact therebetween. Alternatively, the hollow needle may be attached to the first connection surface, for example using a conductive adhesive, or by soldering or welding connections. The external conductor may be electrically connected to the second connecting surface in a similar manner.

The shape of the first connecting surface may be complementary to that of the hollow needle. This may improve the electrical connection between the first connection surface and the hollow needle. It may also serve to hold the hollow needle in place to prevent unwanted movement of the hollow needle. For example, where the hollow needle has a circular cross-section, the first connecting surface may be a round surface with a radius of curvature that matches the radius of the cross-section of the hollow needle. Similarly, the shape of the second connecting surface may be complementary to the shape of the outer conductor.

In some embodiments, the body of the grounding element may have a first channel extending therethrough, the first connecting surface being formed in the first channel. The grounding element may have a generally cylindrical or conical shape and the first channel is a centrally disposed aperture in which a portion of the hollow needle can be received. The first channel may extend through the body in a longitudinal direction, ie in a direction parallel to the longitudinal axis of the inner conductor. The first channel may be an open channel, eg, may constitute a groove in which a portion of the hollow needle is received. Alternatively, the first channel may be a closed channel, for example forming a lumen containing a portion of a hollow needle. A first channel may be provided to hold the hollow needle in place at the grounding element. This may ensure that the electrical connection between the hollow needle and the first connection surface is maintained. The first channel may also be provided to limit lateral movement of the hollow needle, eg in a direction perpendicular to the longitudinal direction. The first connection surface may be provided on one surface of the first channel, for example, the first connection surface may be on a wall of the channel. If the body of the grounding element is made of a conductive material, the wall of the first channel may provide a first connection surface. The shape of the first channel may be complementary to that of the hollow needle.

Where the hollow needle is movable relative to the instrument tip, the first channel may provide a slidingly movable electrical connection between the hollow needle and the grounding element. Thus, the hollow needle can slide relative to the outer conductor and the electrical connection between the hollow needle and the outer conductor can pass across the sliding interface. The first channel may also function to guide the hollow needle when moved relative to the tip.

In some embodiments, the first channel may include a flared portion located at one proximal end of the first channel, the flared portion having an increasing cross-sectional area towards the proximal end of the first channel. have The flared portion may be provided to guide the hollow needle into the first channel or to insert it in the form of a “funnel”.

In some embodiments, the body of the grounding element may include a second channel extending therethrough, the second connecting surface being formed in the second channel; One distal portion of the outer conductor may be received in the second channel. The second channel may extend through the body in a longitudinal direction. The second channel may be parallel to the first channel. The second channel may be an open channel, eg, may constitute a groove in which the distal portion of the outer conductor is received. Alternatively, the second channel may be a closed channel, for example forming a lumen containing the distal portion of the outer conductor. A second channel may be provided to hold the external conductor in place at the grounding element. This can ensure that the electrical connection between the outer conductor and the second connection surface is maintained. The second connection surface may be provided on a surface of the second channel, for example the first connection surface may be on a wall of the channel. If the body of the grounding element is made of a conductive material, one wall of the second channel may provide a second connection surface. The shape of the second channel may be complementary to that of the hollow needle. The distal portion of the outer conductor may be a portion of the outer conductor located at or near the distal end of the coaxial supply cable. A distal portion of the outer conductor may extend to the instrument tip.

The body of the grounding element may include a proximal portion coupled to a distal portion of the coaxial supply cable. A proximal portion of the body of the grounding element may be provided to secure the grounding element to the coaxial supply cable. This may serve to strengthen the interface between the coaxial feed cable and the instrument end. This configuration may also be provided to hold the hollow needle in place relative to the coaxial feed cable. The distal portion of the coaxial supply cable may be secured to the proximal portion of the body by any suitable means. For example, the proximal portion of the body may include a channel in which the distal portion of the coaxial supply cable is received and secured. The body of the grounding element may further comprise a distal portion, wherein the first and second connection surfaces are located at the distal portion. The body of the grounding element may be arranged over the interface between the coaxial supply cable and the instrument end, the proximal portion of the body being located at the distal end of the coaxial supply cable and the distal portion of the body being located at the instrument end. Accordingly, a grounding element may be provided to improve the integrity of the electrosurgical instrument and reduce interference due to the hollow needle.

In some embodiments, the electrosurgical instrument may further include a first insulating sleeve disposed at a proximal end of the grounding element to guide the hollow needle into contact with the first connection surface. The first insulating sleeve may be made of a flexible insulating material (eg, polyimide tube). A first insulating sleeve may be provided to protect and insulate the hollow needle from its periphery. The first insulating sleeve may define a passage through which the hollow needle extends and guides the hollow needle into contact with the first connecting surface. The first insulating sleeve may extend longitudinally from a proximal end of the grounding element toward a proximal end of the instrument. In this way, the first insulating sleeve may be provided to align the hollow needle along the longitudinal direction. The first insulating sleeve may be particularly advantageous where the hollow needle is movable as it may serve to guide the movement of the hollow needle in the longitudinal direction.

In some embodiments, the electrosurgical instrument may further include a second insulating sleeve arranged at one distal end of the grounding element to insulate the hollow needle from the radiating structure. The second insulating sleeve may be made of a flexible insulating material (eg, polyimide tube). A second insulating sleeve may be provided to insulate the hollow needle from the radiating structure and other components of the instrument tip. The second insulating sleeve may define a passageway through which the hollow needle extends. The second insulating sleeve may guide the hollow needle from the distal end of the grounding element towards one distal end of the instrument tip. For example, the second insulating sleeve may extend from the distal end of the grounding element to the distal end of the instrument tip.

In some cases, the first and second insulating sleeves may form a continuous insulating sleeve, the continuous insulating sleeve having an aperture through which the hollow needle is electrically connected to the first connection surface.

When the electrosurgical instrument includes both the first insulating sleeve and the second insulating sleeve, the first insulating sleeve may have a larger cross-section than the second insulating sleeve. This may facilitate insertion of the hollow needle into the first insulating sleeve to bring the hollow needle into electrical contact with the grounding element. In this way, the larger first insulating sleeve can function to insert the hollow needle in a “funnel” form towards the first connection surface and the grounding element. The use of a larger diameter first insulating sleeve may reduce drag to the hollow needle when moved relative to the instrument tip. This may facilitate movement of the hollow needle relative to the instrument tip.

A cross-section of the second insulating sleeve may approximately coincide with a cross-section of the hollow needle. In this way, the second insulating sleeve can ensure the correct positioning of the hollow needle within the instrument tip.

In some embodiments, the hollow needle comprises: a retracted position in which one distal end of the hollow needle is set back from one distal end of the instrument tip; and an exposed position in which the distal end of the hollow needle protrudes beyond the distal end of the instrument tip. In this way, the hollow needle can be arranged in a retracted position to prevent accidental tissue damage when not in use. The needle may be moved to the exposed position when it is desired to deliver fluid to the treatment site, eg, to administer a drug to the treatment site. The hollow needle is movable relative to the instrument tip in the longitudinal direction. The distal end of the hollow needle may be positioned within the instrument tip when the hollow needle is in the retracted position. The instrument tip may include a channel through which the hollow needle is movable, the distal end of the hollow needle being positioned within the channel when the hollow needle is in the retracted position.

The hollow needle may be movable relative to the instrument tip by any suitable mechanism. In some embodiments, the hollow needle may be moved by actuating (eg, pushing or pulling) a control wire attached to the hollow needle. A control wire may be positioned within the fluid channel, and the control wire may be coupled to a hollow needle within the fluid channel. Alternatively, the control wire may be arranged along the fluid channel.

The electrical connection between the hollow needle and the outer conductor may be configured to allow movement of the hollow needle relative to the instrument tip. In this way, the hollow needle can remain electrically connected to the external conductor, whether in a retracted position or an exposed position. For example, the electrical connection between the hollow needle and the outer conductor may be a slidingly movable electrical connection. If the grounding element comprises a body having a first connecting surface, the hollow needle can be slid relative to the first connecting surface. In some cases, the hollow needle may be completely withdrawn from the instrument so that it is no longer electrically connected to the external conductor.

Where the grounding element comprises a first channel, the first channel may be dimensioned such that the hollow needle can slide longitudinally along the channel while the hollow needle remains in contact with the first connecting surface.

The connection between the hollow needle and the fluid channel may be configured to allow movement of the hollow needle relative to the fluid channel. In this way, when the hollow needle is moved relative to the instrument tip, the hollow needle can remain in fluid communication with the fluid channel. For example, if one proximal end of the hollow needle is positioned within the fluid channel, the proximal end of the hollow needle may be moved along the length of the fluid channel. A sliding seal may be formed between the hollow needle and the fluid channel to allow movement of the hollow needle relative to the fluid channel while preventing fluid from escaping at the joint between the hollow needle and the fluid channel. .

In some embodiments, the instrument tip may include an opening at its distal end, wherein when the hollow needle is in the retracted position the distal end of the hollow needle may be positioned at the instrument tip and does not protrude through the opening, the hollow The distal end of the hollow needle may protrude through the opening when the needle is in the exposed position. In this way the hollow needle can be protected inside the instrument tip when in the retracted position.

In some embodiments, the hollow needle, when in the exposed position, can be electrically connected to the external conductor at a location on the hollow needle corresponding to an integer number of half-waves of microwave energy spaced apart from one distal end of the hollow. For example, the grounding element may be positioned half-wave away from the distal end of the hollow needle. This can ensure that at microwave frequencies the distal end of the needle is at the same voltage as the portion of the needle grounded to an external conductor. This can reduce interference due to the hollow needle. Where the needle is movable relative to the instrument tip, the retracted position and the exposed position may be set such that, at each position, the distal end of the hollow needle is an integer number of wavelengths spaced from the grounded position. Accordingly, it is possible to minimize the interference that occurs when the hollow needle is in the retracted position and the exposed position.

In some embodiments, the instrument tip may further include a dielectric body, and an energy transfer structure (ie, a radiating structure) may be formed within and/or over the dielectric body. The dielectric body may be made of any suitable dielectric (insulating) material. The material of the dielectric body may be selected to improve impedance matching with the target tissue to improve the efficiency with which EM energy is delivered to the target tissue. In some cases, the dielectric body may include a plurality of different portions of dielectric material that are selected and arranged to form a radiation profile in a desired manner. The dielectric body may serve as a support for the radiating structure, for example portions of the radiating structure may be formed on or within the dielectric body.

The dielectric body may be a cylinder having a longitudinal axis aligned with the coaxial cable, the dielectric body including a longitudinally extending channel formed therein, and a portion of the hollow needle being received in the longitudinally extending channel. A channel in the dielectric body may be provided to hold a position of the hollow needle at the instrument tip. In this way, the channels of the dielectric body may limit or prevent lateral movement of the hollow needle. This allows for precise placement of the hollow needle to facilitate insertion of the hollow needle into the target tissue. A channel of the dielectric body may be open, for example formed by a groove in one surface of the dielectric body, or it may be closed, for example, a tunnel (passage) through a portion of the dielectric body. ) can be formed by When the channel is open, it may be formed between two ridges of the dielectric body. Where the instrument includes a second insulating sleeve, the second insulating sleeve may extend within the channel of the dielectric body to isolate the hollow needle from the radiating structure.

An opening at the distal end of the instrument tip may be formed at one distal end of the channel of the dielectric body.

In some embodiments, the radiating structure may include a first electrode electrically connected to the inner conductor, and a second electrode electrically connected to the outer conductor, the first electrode and the second electrode being exposed to the surface of the dielectric body. . The first and second electrodes may function as bipolar RF electrodes, eg, as active and return electrodes, respectively, when RF energy is delivered to the instrument tip. In this way, biological tissue located in the region surrounding the first and second electrodes may be ablated and/or coagulated with RF energy. The first and second electrodes may be arranged on the surface of the dielectric body to obtain a desired treatment profile. The first electrode may be electrically connected to the inner conductor by an intermediate conductor extending through a portion of the dielectric body.

The first and second electrodes may be configured to treat tissue with RF and/or microwave frequencies. For example, when RF energy is delivered to the instrument tip, the first and second electrodes may function as bipolar RF electrodes. When microwave energy is delivered to the instrument tip, the first and second electrodes may function as a bipolar microwave antenna. Advantageously, this allows the user to quickly switch between treatment modalities (eg RF coagulation and microwave ablation) without changing electrosurgical instruments during surgery.

In some embodiments, the second electrode may be electrically connected to the external conductor by a grounding element. In this way, the hollow needle and the second electrode can be electrically connected to the external conductor by means of a grounding element. As a result, only a single electrical connection need be arranged on the outer conductor, ie only one between the outer conductor and the grounding element. This may facilitate electrically connecting the second electrode to the external conductor.

In some embodiments, the dielectric body may include a first groove in which a first electrode is disposed and a second groove in which a second electrode is disposed. A thickness of the dielectric material of the dielectric body may be disposed between the first groove and the second groove, the first and second electrodes being separated by a thickness of the dielectric material. The thickness of the first electrode may correspond to the depth of the first groove, and the first electrode is arranged flush with the outer surface of the dielectric body. Similarly, the thickness of the second electrode may correspond to the depth of the second groove, the second electrode being arranged flush with the outer surface of the dielectric body. This can provide a smooth outer surface to the instrument tip. This may prevent any sharp edges of the instrument tip that could get caught in the tissue. The grooves may be indentations or depressions in the outer surface of the dielectric body. In some cases, a groove may be formed between two or more portions of the dielectric body.

In some embodiments, the first electrode can include a first set of longitudinally extending conductive fingers arranged circumferentially around the dielectric body. The conductive fingers of the first electrode may be elongate conductive elements oriented along the longitudinal direction. All of the conductive fingers of the first set are electrically connected together to form a first electrode. The first set of conductive fingers may be substantially parallel and may be arranged around the perimeter of the dielectric body, eg, each conductive finger may be at a different location around the perimeter of the dielectric body. For example, if the dielectric body is cylindrical, the conductive fingers may be parallel to the axis of the cylindrical body and may be positioned at different positions on the sides of the cylindrical body. Multiple conductive fingers arranged around the perimeter of the dielectric body allow biological tissue to be treated in multiple directions around the instrument tip. The first set of conductive fingers may be evenly spaced around the perimeter of the dielectric body. This improves the axisymmetry of the radial profile of the instrument tip and allows for substantially uniform treatment of tissue disposed around the instrument tip. The conductive fingers of the first electrode may be located in the first set of grooves in the dielectric body.

In some embodiments, the second electrode may include a second set of longitudinally extending conductive fingers arranged circumferentially around the dielectric body, the first set and the second set of conductive fingers being the first and second sets of conductive fingers. They may be alternately arranged around the periphery. The conductive fingers of the second electrode may be elongate conductive elements oriented along the longitudinal direction. All of the conductive fingers of the second set are electrically connected together to form the first electrode. The second set of conductive fingers may be substantially parallel and may be arranged around the perimeter of the dielectric body, eg, each conductive finger may be at a different location around the perimeter of the dielectric body. The conductive fingers of the second electrode may be located in a second set of grooves in the dielectric body. The first set of grooves and the second set of grooves may be separated by portions of the dielectric body, and the conductive fingers of the first electrode and the second electrode are electrically isolated from each other by the dielectric body.

The first and second sets of conductive fingers may be alternately arranged around the perimeter of the dielectric body, for example, the conductive fingers may be ordered to alternate between the first and second sets around the perimeter. In this way, each first set of conductive fingers can be positioned between two conductive fingers of a second set (and vice versa). Accordingly, the first and second electrodes may be interdigitated electrodes. This configuration may be adapted to provide a substantially uniform radiation profile around the instrument tip. This allows, for example, tissue to be uniformly ablated or coagulated in a volume around the instrument tip.

In some embodiments, the instrument tip may further include an annular conductor electrically connected to the outer conductor, the annular conductor forming a portion of the outer surface of the electrosurgical instrument and an electrical connection between the coaxial supply cable and the radiating structure to shield The annular conductor may be a hollow cylindrical portion of a conductive material. An annular conductor may be disposed near one proximal end of the instrument end around the joint between the coaxial supply cable and the radiating structure. The electrical connection between the coaxial supply cable and the radiating structure may include an electrical connection between the inner conductor and a conductive element (eg, an elongated conductor) of the radiating structure. This electrical connection may include a length of unshielded wire between the inner conductor and the radiating structure. Unshielded wires of this length can be susceptible to electrical interference. Since the annular conductor is electrically connected to the outer conductor, it can be provided to shield any wiring or electrical connection located inside the annular conductor from electrical interference. Thus, the annular conductor can reduce interference at the joint between the coaxial supply cable and the radiating structure to improve the performance of the instrument end. Annular conductors may also be provided to physically protect the connection between the coaxial supply cable and the radiating structure by providing a barrier around the connection. The annular conductor may be electrically connected to the external conductor by a grounding element.

In some cases, the annular conductor may constitute a return electrode for RF energy. Where the instrument tip includes first and second electrodes on the surface of the dielectric body, the annular conductor may constitute an extension of the second electrode. This may serve to increase the effective area of the second electrode. In some cases, the annular conductor may be a proximal portion of the second electrode.

In some embodiments, one distal end of the instrument tip may be formed in a smoothly contoured manner to be suitable for providing a pressure spot in the target area. For example, the distal end of the instrument tip may be rounded and/or smoothly tapered. This can be done by pressing the tip of the instrument against the target site to stop bleeding (eg, hemostasis). EM energy can be delivered by the instrument tip to coagulate tissue and stop or control bleeding.

The electrosurgical instruments discussed above may form part of a complete electrosurgical system. For example, the system may include an electrosurgical generator arranged to supply microwave energy and high frequency energy; and an electrosurgical instrument of the present invention coupled to receive microwave energy and high frequency energy from the electrosurgical generator. The electrosurgical instrument may further include a surgical examination device (eg, an endoscope) having a flexible insertion cord for insertion into the body of a patient, the flexible insertion cord having an instrument channel arranged along its length; The electrosurgical instrument is dimensioned to fit within the instrument channel.

In the present specification, "microwave" may be used broadly to denote the frequency range of 400 MHz to 100 GHz, preferably the range of 1 GHz to 60 GHz. Preferred spot frequencies for microwave EM energy include 915 MHz, 2.45 GHz, 3.3 GHz, 5.8 GHz, 10 GHz, 14.5 GHz and 24 GHz. 5.8 GHz may be desirable. Conversely, in this specification, "high frequency" or "RF" is used to refer to a frequency range of at least three times lower frequency, eg, up to 300 MHz. Preferably, the RF energy has a frequency high enough to prevent nerve stimulation (eg, greater than 10 kHz) and a frequency low enough to prevent tissue blanching or thermal spread (eg, less than or equal to 10 MHz). . A preferred frequency range for RF energy may be between 100 kHz and 1 MHz.

As used herein, the terms “proximal” and “distal” mean that the ends of the electrosurgical instrument are positioned away from and close to the treatment site, respectively. Thus, in use, the proximal end of the electrosurgical instrument is positioned proximate to the generator to provide RF and/or microwave energy, and the distal end is positioned proximate to the treatment site, i.

As used herein, the term “conductive” means electrically conductive, unless otherwise indicated.

As used below, the term "longitudinal" refers to a direction along the length of the electrosurgical instrument parallel to the axis of the coaxial transmission line. The term “inner” means radially close to the center (eg, axis) of the instrument. The term “outer” means radially away from the center (axis) of the instrument.

The term “electrosurgical” is used during surgery and is used in reference to instruments, devices or instruments that use microwave and/or high frequency electromagnetic (EM) energy.

Now, embodiments of the present invention will be described below by way of example with reference to the accompanying drawings:
1 is a schematic diagram of an electrosurgical system that is one embodiment of the present invention;
Fig. 2 is a perspective view of an electrosurgical instrument in one embodiment of the present invention, the hollow needle of the instrument in a retracted position;
Fig. 3 is a perspective view of the electrosurgical instrument of Fig. 2, with the hollow needle in an exposed position;
Fig. 4 is a schematic cross-sectional view of the electrosurgical instrument of Fig. 2;
Fig. 5 is a perspective view of the electrosurgical instrument of Fig. 2, wherein the instrument's flexible instrument sleeve is omitted to show the internal structure of the instrument;
6-8 are schematic cross-sectional views of the electrosurgical instrument of FIG. 2 showing the hollow needle in different positions;
9A and 9B are perspective views of a grounding element that may be used in an electrosurgical instrument that is one embodiment of the present invention; 10A is a front view of a dielectric body that may be used in an electrosurgical instrument according to an embodiment of the present invention;
Fig. 10B is a perspective view of the dielectric body of Fig. 10A;

1 is a schematic diagram of a complete electrosurgical system 100 capable of supplying microwave energy and radiofrequency energy to the distal end of an invasive electrosurgical instrument. System 100 includes a generator 102 for controllably supplying microwave and radio frequency energy. A suitable generator for this purpose is described in WO 2012/076844, the international application of which is hereby incorporated by reference. The generator may be arranged to monitor the reflected signal received from the instrument to determine an appropriate power level for delivery. For example, the generator may be arranged to calculate the impedance visible at the distal end of the generator to determine an optimal delivered power level. The generator 102 is connected to the interface joint 106 by an interface cable 104 .

System 100 also includes a fluid supply unit 108 containing a fluid for use with an electrosurgical instrument. The fluid may be a liquid (eg, a liquid drug) or a gas (eg, argon gas). The fluid supply unit 108 is fluidly connected to the interface joint 106 by a fluid conduit 109 . The fluid supply unit 108 may distribute the fluid contained therein by the fluid conduit 109 . For example, the fluid supply unit 108 may include a syringe for dispensing a liquid medicament.

The interface joint 106 accommodates an instrument control mechanism operable by sliding the trigger 110, for example, to regulate longitudinal (fore and aft) motion of one or more control wires or pushrods (not shown). If there are multiple control wires, there can be multiple sliding triggers on the interface joint for complete control. The function of the interface joint 106 is to couple inputs from the generator 102 , the fluid supply unit 108 and the instrument control mechanism to a single flexible shaft 112 extending from the distal end of the interface joint 106 . will be. In other embodiments, other types of inputs may also be coupled to the interface joint 106 .

The flexible shaft 112 can be inserted through the entire length of the instrument (working) channel of the endoscope 114 . The flexible shaft 112 passes through the instrument channel of the endoscope 114 and is configured to protrude from the distal end of the instrument channel of the endoscope (eg, into a patient) with a distal assembly 118 (shown in scale in FIG. 1 ). does not have). Distal end assembly 118 includes an instrument tip for delivering microwave energy and radio frequency energy into biological tissue. The tip is also configured to deliver fluid from the fluid supply unit 108 . End configurations are discussed in more detail below.

The structure of the distal assembly 118 may be arranged to have a maximum outer diameter suitable for passing through the working channel. In general, in a surgical inspection device such as an endoscope, the diameter of the working channel is less than 4.0 mm, for example, any one of 2.8 mm, 3.2 mm, 3.7 mm, and 3.8 mm. The length of the flexible shaft 112 may be 0.3 m or more, for example 2 m or more. In another example, the distal assembly 118 may be mounted to the distal end of the flexible shaft 112 after the shaft is inserted through the working channel (and before the instrument cord is inserted into the patient). Alternatively, the flexible shaft 112 may be inserted into the working channel from the distal end prior to forming the proximal connection. In this arrangement, the distal end assembly 118 may have a larger dimension than the working channel of the surgical examination device 114 .

The system described above is one way to insert an instrument into a patient's body. Other techniques are possible. For example, the instrument may be inserted using a catheter.

2 shows a perspective view of one distal end of an electrosurgical instrument 200 that is an embodiment of the present invention. The distal end of the electrosurgical instrument 200 may correspond, for example, to the distal assembly 118 discussed above. 3 shows another perspective view of the electrosurgical instrument 200 . 4 shows one cross-sectional side view of an electrosurgical instrument 200 . 5 shows one perspective view of an electrosurgical instrument 200, wherein the instrument's flexible instrument sleeve has been omitted to show the internal structure of the instrument.

The electrosurgical instrument 200 includes a coaxial supply cable 202 connectable from its proximal end to a generator (eg, generator 102 ) for delivering microwave energy and RF energy. The coaxial supply cable 202 includes an inner conductor 204 and an outer conductor 206 separated by a dielectric material 208 . The coaxial supply cable 202 is preferably low loss to microwave energy. A choke (not shown) may be provided on the coaxial supply cable 204 to suppress back propagation of microwave energy reflected from the distal end and thus limit back heating along the device. To insulate and protect the coaxial supply cable 202 , an insulating coating 209 is provided on the outer surface of the outer conductor 206 .

The electrosurgical instrument 200 further includes a fluid channel 210 extending along the coaxial supply cable 202 . A fluid channel 210 may be provided to deliver fluid from the proximal end of the instrument to the distal end of the instrument. For example, one proximal end of the fluid channel 210 may be connected to the fluid supply unit 108 . Both the coaxial supply cable 202 and the fluid channel 210 are received within the flexure sleeve 212 . The flexible instrument sleeve 212 may be made of or coated with a biocompatible non-stick material (eg, PTFE) to prevent tissue from sticking to the sleeve.

The electrosurgical instrument 200 includes an instrument end 214 located at one distal end of the coaxial supply cable 202 . The instrument tip 214 includes a dielectric body 216 made of an insulating material (eg, PEEK). The dielectric body 216 has a radiating structure formed on its outer surface, the radiating structure comprising an inner electrode 218 and an outer electrode 220 . The inner electrode 218 is electrically connected to the inner conductor 204 of the coaxial supply cable 202 by an electrical connection 222 (see FIG. 4 ). The structure of the inner conductor 204 is discussed in more detail below with reference to FIGS. 10A and 10B , which show an isolated dielectric body 216 . Electrical connections 222 may be, for example, soldered or welded electrical connections, or may be formed using a conductive adhesive (eg, conductive epoxy). The electrical connection 222 between the inner conductor 204 and the inner electrode 218 may be potted, for example, surrounded by a solid or gelatinized compound for protection.

Instrument tip 214 further includes a grounding element 224 positioned near the proximal end of instrument tip 214 . Grounding element 224 may be made of a conductive material (eg, metal) and formed of a single component. The structure of the grounding element 224 is illustrated in greater detail in FIGS. 9A and 9B , which show perspective views of the grounding element 224 . A first channel 226 and a second channel 228 extending in the longitudinal direction are formed in the ground element 224 . The first channel 226 is a closed channel and is configured to receive a hollow needle as described below. The second channel 228 is formed by an open channel, that is, a groove in the outer surface of the grounding element 224 . One distal portion of the coaxial supply cable 202 is secured to the second channel 228 of the grounding element 224 . The shape of the second channel 228 is complementary to that of the distal portion of the coaxial supply cable 202 . The second channel 229 may be shaped (eg, by an interference fit) to secure the coaxial feed cable 202 . In some cases, the outer conductor 206 may be secured to the grounding element 224 using, for example, a conductive epoxy.

The insulating coating 209 is peeled off from the distal portion of the coaxial cable 202 secured to the second channel 228 of the grounding element 224 . In this way, the outer conductor 206 at the distal portion of the coaxial supply cable 202 is exposed and in electrical contact with one surface of the second channel 228 of the grounding element 224 . In this way, the outer conductor 206 is electrically connected to the ground element 224 .

The second electrode 220 includes a proximal portion 230 extending towards the proximal end of the instrument tip 214 . The proximal portion 230 is formed by a cylindrical hollow conductor disposed around the distal portion of the coaxial supply cable 202 and the grounding element 224 . The proximal portion 230 is in electrical contact with the exposed portion of the outer conductor 206 and the outer surface of the grounding element 224 . In this way, the second electrode 220 is electrically connected to the external conductor 206 . A proximal portion 230 of the second electrode 220 may be provided to secure the outer conductor 206 relative to the grounding element 224 such that an electrical connection between the grounding element 224 and the outer conductor 206 is maintained. can The grounding element 224 includes a lip 232 to which the proximal portion 230 of the second electrode 220 abuts. This may serve to maintain the relative position of the proximal portion 230 and the grounding element. The proximal portion 230 of the external electrode 220 may be soldered to the external conductor 206 and/or a grounding element, or secured using some other means (eg, conductive epoxy).

The instrument tip further includes an outer annular conductor 231 disposed around the proximal portion 230 of the outer electrode 220 . The annular conductor 231 is a hollow cylindrical portion of conductive material. The annular conductor 231 is electrically connected to the proximal portion 230 of the outer electrode 220 . The annular conductor 231 is arranged to shield the electrical connection 222 between the inner conductor 204 and the inner electrode 218 . Thus, the annular conductor 231 can protect the electrical connection 222 from electrical interference as well as protect the electrical connection from physical damage.

A needle passageway is formed in the instrument tip 214 to receive a hollow needle 234 in fluid communication with the fluid channel 210 . The hollow needle 234 may be moved relative to the instrument tip 214 through the needle passageway as discussed below with respect to FIGS. 6-8 . For the sake of illustration, the hollow needle 234 has been omitted from FIG. 4 .

The needle passageway is defined by multiple components of the instrument tip 214 . At its proximal end, the needle passageway is defined by the first channel 226 of the grounding element 224 . The first channel 226 includes a flared portion 236 at its proximal end. The flared portion 236 is flared outwardly, ie, the cross-sectional area of the flared portion 236 increases towards the proximal end of the first channel 226 . The flared portion 236 may be provided to guide (eg, bias or funnel) the hollow needle 234 into the first channel 226 . A first insulating sleeve 238 extends from the first channel 226 in a proximal direction towards the fluid channel 210 . A first insulating sleeve 238 may be provided to guide the hollow needle 234 into the first channel 226 towards the grounding element 224 . The first channel 226 further includes a contact 240 . The contact portion 238 of the first channel 226 has a cross-section that substantially coincides with the cross-section of the hollow needle 234 , that is, the shape of the contact portion 238 may be complementary to that of the hollow needle 234 . . In this way, when the hollow needle 234 extends through the contact 240 of the first channel 226 , the hollow needle 234 is configured to form electrical contact between the hollow needle 234 and the grounding element 224 . ) may contact one surface of the first channel 226 (eg, one wall of the first channel 226 ). This may serve to short the hollow needle 234 connected to the outer conductor 206 . The outer conductor 206 may be generally grounded (eg, may be 0V) so that the hollow needle 234 may also be grounded when in the first channel 226 .

The needle passageway further includes a second insulating sleeve 242 extending from the distal end of the first channel 226 . A second insulating sleeve 242 extends through the distal end 214 into an opening 244 at the distal end of the distal end 214 . A second insulating sleeve 242 passes through a channel 246 in the dielectric body 216 . A second insulating sleeve 242 is provided to electrically isolate the hollow needle 234 from the inner electrode 218 .

The cross section of the second insulating sleeve 242 is smaller than the cross section of the first insulating sleeve 238 . The cross-section of the second insulating sleeve 238 is approximately the same size as the cross-section of the contact portion 238 of the first channel 226 . This may be provided to ensure the correct positioning of the hollow needle 234 as it moves through the instrument tip 214 . By using a larger cross-section for the first insulating sleeve 238 as compared to the second insulating sleeve 242 (eg, due to friction between the hollow needle 234 and the insulating sleeve), the hollow needle 234 is ) can be reduced in resistance to movement along the needle passage. This may facilitate movement of the hollow needle 234 relative to the instrument tip 214 .

The hollow needle 234 is in fluid communication with the fluid channel 210 . A hollow needle 234 extends from one distal end of the fluid channel towards the instrument tip 214 . To facilitate insertion of the hollow needle 234 into tissue, one distal end 248 of the hollow needle 234 is pointed. Hollow needle 234 may be a hollow tube made of a material suitable for injecting fluid into tissue, such as, for example, stainless steel. For example, the hollow needle 234 may be a hypodermic needle. One proximal portion of the hollow needle 234 is received in the distal portion of the fluid channel 210 , and fluid delivered by the fluid channel 210 may flow into the hollow needle 234 . To prevent fluid leakage, a seal may be formed between the fluid channel 210 and the hollow needle 234 .

6-8 show cross-sectional side views of the electrosurgical instrument 200 with the hollow needle 234 in different positions. In FIG. 6 , the hollow needle is in a first retracted position such that the distal end 248 is positioned within the first insulating sleeve 238 . In FIG. 7 , the hollow needle 234 is in the second retracted position and the distal end 248 is positioned inside the second insulating sleeve 242 so that it does not protrude through the opening 244 at the distal end 214 . . In FIG. 8 , hollow needle 234 is in an exposed position, distal tip 248 protrudes through opening 244 , and a distal portion of hollow needle 234 extends beyond instrument tip 214 .

The hollow needle 234 may be moved between the positions illustrated in FIGS. 6-8 by any suitable means. For example, the hollow needle 234 may be moved using a control wire (not shown) that extends through the fluid channel 210 to the proximal end of the instrument 200 .

When the hollow needle 234 is in the first retracted position ( FIG. 6 ), the hollow needle is fully withdrawn from the instrument tip 214 , ie not positioned at the instrument tip 214 . In this configuration, the hollow needle 234 is not electrically connected to the external connector 206 . When the hollow needle 234 is fully withdrawn from the instrument tip 214 , the hollow needle 234 does not interfere with the microwave energy emitted from the instrument tip (ie, by the inner and outer electrodes 218 , 220 ).

When the hollow needle 234 is in the second retracted position ( FIG. 7 ), the distal end 248 of the hollow needle 234 is positioned at the instrument tip 214 . In this configuration, a portion of the hollow needle 234 is received within the contact portion 240 of the first channel 226 of the grounding element 224 . In this way, the hollow needle 234 is electrically connected to the grounding element 224 at the contact 240 . As a result, the hollow needle 234 is electrically connected to the outer conductor 206 of the coaxial supply cable 202 by a grounding element 224 . This may reduce or prevent interference of the hollow needle 234 with the EM energy emitted by the instrument tip 214 (ie, by the inner and outer electrodes 218 , 220 ).

When the hollow needle 234 is in the exposed position ( FIG. 8 ), the hollow needle 234 projects through the opening 244 at the instrument tip 214 . In this configuration, the hollow needle 234 may be used to dispense fluid from the fluid conduit 210 to the treatment site. For example, the pointed distal end 248 of the hollow needle 234 may be inserted into the target tissue to inject a liquid drug into the target tissue. Similar to the second retracted position, a portion of the hollow needle 234 is received in the contact portion 240 of the first channel 226 of the grounding element 224 . As a result, the hollow needle 234 is electrically connected to the outer conductor 206 of the coaxial supply cable 202 by a grounding element 224 , thereby reducing interference caused by the hollow needle 234 . have. Thus, it is possible to avoid the hollow needle 234 from interfering with the radiated EM energy, regardless of whether the hollow needle 234 is in the first retracted position, the second retracted position or the exposed position.

Accordingly, the electrical contact formed between the hollow needle 234 and the contact 240 of the first channel 226 may be at the sliding interface between the needle and the grounding element, ie between the hollow needle 234 and the grounding element 224 . The hollow needle 234 may be moved through the first channel 226 while maintaining electrical contact.

The grounding element 224 is configured to provide an integer number of half wavelengths (of the delivered microwave energy) spaced apart from the distal end 248 of the hollow needle 234 when the hollow needle is in the second retracted and/or exposed position. ) may be located at the instrument end 214 . This ensures that, at microwave frequencies, the distal end 248 of the hollow needle 234 and the portion of the hollow needle 234 of the first channel 226 are at the same voltage (ie, the voltage of the outer conductor 206 ). can do. For example, for a microwave energy frequency of 5.8 GHz, a quarter wavelength of microwave energy might be about 12.9 mm (assuming the waveguide is unloaded). If the hollow needle 234 is shorted to ground (eg, 0V) spaced 2×12.9 mm from the distal end 248 , the distal end 248 may also be shorted to ground. Thus, in this example, the grounding element 224 would be disposed about 2 x 12.9 mm = 25.8 mm from the distal end 248 of the hollow needle 234 when the hollow needle 234 is in the exposed position. can The distance of travel of the needle may be set such that the electrical connection to the grounding element 224 is multiple half-wavelengths of microwave energy from the distal end in both the retracted and exposed positions.

10A shows a front view of the dielectric body 216 of the instrument tip 214 . 10B shows a perspective view of the dielectric body 216 of the instrument tip 214 . The dielectric body 216 is formed of an integral insulating material (eg, PEEK). The dielectric body 216 includes a first set of grooves 250a, 250b, 250c in which the inner electrode 218 is formed and a second set of grooves 252a, 252b, 252c in which the outer electrode 220 is formed. . A first set of grooves 250a - c and a second set of grooves 252a - c are formed in the outer surface 254 of the dielectric body 216 and extend longitudinally. In the example shown, both the first set of grooves 250a-c and the second set of grooves 252a-c include three grooves. In other examples, different numbers of grooves may be used. The first and second sets of grooves are alternately arranged around the periphery of the dielectric body 216 . Accordingly, each groove of the first set 250a-c is positioned between two grooves of the second set 252a-c. Adjacent grooves in the dielectric body 216 are separated by a portion of the dielectric body 216 . The outer surface 254 of the dielectric body 216 has a generally cylindrical shape and forms part of the outer surface of the instrument tip 214 . The distal end 256 of the dielectric body 216 is formed, for example, in a smoothly contoured manner.

The inner electrode 218 is formed by an integral conductive material (eg, metal) having three longitudinally extending conductive fingers 258a, 258b, 258c. A respective conductive finger 258a - c is positioned in each of the first set of grooves 250a - c in the dielectric body 216 . The external electrode 220 is formed by an integral conductive material (eg, metal) having three longitudinally extending conductive fingers 260a, 260b, 260c. Each conductive finger 260a - c is positioned in each of the second set of grooves 252a - c in the dielectric body 216 . The conductive fingers 258a - c of the inner electrode 218 are electrically isolated from the conductive fingers 260a - c of the outer electrode 220 by a dielectric body 216 . Each conductive finger of the inner electrode 218 is positioned between two conductive fingers of the outer electrode (and vice versa). In this way, inner electrode 218 and outer electrode 220 can be considered as interdigitated electrodes.

The inner electrode 218 and the outer electrode 220 are formed to be flush with the distal end 256 and the outer surface 254 of the dielectric body 216 . This may provide a smooth outer surface to the instrument tip 214 to prevent tissue from snagging on the instrument tip 214 . The instrument tip 214 is coated with a biocompatible non-stick coating made of, for example, Parylene C or Parylene D. In this example, the thickness of the coating is about 3 μm, but other thicknesses may be used, such as up to 40 μm. Alternatively or in addition, inner electrode 218 and outer electrode 220 may be polished to minimize tissue adhesion.

The non-stick coating prevents the clotted tissue from sticking to the tip of the instrument. As a result, damage to the tissue can be prevented when the instrument tip 214 is removed from the treatment site after application of EM energy.

The electrosurgical instrument 200 may be particularly suitable for coagulating tissue using microwave energy to prevent or control (hemostasis) bleeding. The inner electrode 218 and the outer electrode 220 may function as a bipolar microwave antenna when microwave energy is delivered to the instrument tip 214 by a coaxial supply cable 202 . In this way, target tissue positioned around the instrument tip 214 may be coagulated using microwave energy. The rounded distal end of the instrument tip 214 may define an instrument tip suitable for providing pressure to a treatment area (eg, a blood vessel) to function as a tamponade to stop bleeding. Microwave energy may be provided by instrument tip 214 while pressure is applied to the treatment area to coagulate tissue and prevent bleeding.

The conductive fingers of the outer electrode 220 and the inner electrode 218 are alternately arranged around the perimeter of the instrument tip 214 , such that the microwave radiation profile generated by the instrument tip is substantially uniform around the instrument tip 214 . can This allows for substantially uniform treatment of tissue positioned around the instrument tip 214 .

Claims (25)

An electrosurgical instrument, wherein the electrosurgical instrument comprises:
a coaxial supply cable for transmitting microwave energy, the coaxial supply cable having an inner conductor, an outer conductor and a dielectric material separating the inner and outer conductors;
an instrument end disposed at a distal end of the coaxial supply cable for receiving microwave energy and/or radio frequency energy; and
a fluid channel for delivering fluid to the instrument tip;
where the instrument end is:
a radiating structure for radiating microwave energy into biological tissue; and
a hollow needle in fluid communication with the fluid channel, wherein the hollow needle is arranged to deliver fluid from the fluid channel to the treatment site; and
An electrosurgical instrument, characterized in that the radiating structure is coated with an insulating non-stick material. The electrosurgical instrument of claim 1 , wherein the instrument tip is coated with an insulating non-stick material. 3. Electrosurgical instrument according to claim 1 or 2, characterized in that the coating of insulating non-stick material on the radiating structure has a thickness of 40 μm or less. The electrosurgical instrument according to claim 3, wherein the thickness is 10 μm or less. Electrosurgical instrument according to any one of the preceding claims, characterized in that the insulating non-stick material is Parylene C or Parylene D. An electrosurgical instrument, wherein the electrosurgical instrument comprises:
a coaxial supply cable for transmitting microwave energy and/or high frequency energy, the coaxial supply cable having an inner conductor, an outer conductor and a dielectric material separating the inner and outer conductors;
an instrument end disposed at a distal end of the coaxial supply cable for receiving microwave energy and/or radio frequency energy; and
a fluid channel for delivering fluid to the instrument tip;
where the instrument end is:
an energy transfer structure for delivering microwave energy and/or radio frequency energy to a biological tissue; and
a hollow needle in fluid communication with a fluid channel, wherein the hollow needle is arranged to deliver fluid from the fluid channel to the treatment site;
The energy transfer structure comprises a radiation structure for radiating microwave energy into biological tissue, and
The hollow needle is electrically connected to an external conductor to ground the hollow needle. The electrosurgical instrument of any one of the preceding claims, wherein the instrument tip further comprises a grounding element arranged to electrically connect the hollow needle to the external conductor. 8. The grounding element of claim 7, wherein the grounding element comprises a body having a first connecting surface and a second connecting surface arranged to hold a hollow needle and an outer conductor, respectively, the first connecting surface and the second connecting surface being together electrically connected, the hollow needle electrically connected to the first connecting surface and the external conductor electrically connected to the second connecting surface. 9. The method of claim 8:
the body of the grounding element has a first channel extending therethrough, the first connection surface being formed in the first channel;
a portion of the hollow needle is received in the first channel; and
The first channel includes a flared portion positioned at a proximal end of the first channel, the flared portion having a cross-sectional area that increases toward the proximal end of the first channel. 10. The method of claim 8 or 9:
the body of the grounding element includes a second channel extending therethrough, the second connecting surface being formed in the second channel; and
and a distal portion of the outer conductor is received in the second channel. 11. The method of any one of claims 8 to 10, further comprising:
a first insulating sleeve arranged at one proximal end of the grounding element for guiding the hollow needle into contact with the first connecting surface, and
and a second insulating sleeve arranged at one distal end of the grounding element to insulate the hollow needle from the radiating structure. The method of any one of the preceding claims, wherein the hollow needle comprises:
a retracted position in which one distal end of the hollow needle is set back from one distal end of the instrument tip; and
An electrosurgical instrument, wherein the distal end of the hollow needle is movable between an exposed position that protrudes beyond the distal end of the instrument tip. 13. The electrosurgical instrument of claim 12, wherein the hollow needle is slidable relative to the outer conductor, and an electrical connection between the hollow needle and the outer conductor passes across the sliding interface. 14. The device of claim 12 or 13, wherein the instrument tip comprises an opening at its distal end, wherein:
When the hollow needle is in the retracted position, the distal end of the hollow needle is located at the instrument tip and does not protrude through the opening;
When the hollow needle is in the exposed position, the distal end of the hollow needle protrudes through the opening. 15. A position on the hollow needle according to any one of claims 12 to 14, wherein, when in the exposed position, the hollow needle is a position on the hollow needle corresponding to an integer number of half wavelengths of microwave energy spaced apart from one distal end of the hollow needle. Electrosurgical instrument, characterized in that electrically connected to the external conductor in the. The electrosurgical instrument according to any one of the preceding claims, wherein the instrument tip further comprises a dielectric body, wherein the radiating structure is formed in and/or on the dielectric body. 17. The method of claim 16, wherein the radiating structure comprises a first electrode electrically connected to the inner conductor, and a second electrode electrically connected to the outer conductor, the first electrode and the second electrode being exposed at the outer surface of the dielectric body. Characterized by an electrosurgical instrument. 18. The electrosurgical instrument of claim 16 or 17, wherein the dielectric body includes a first groove in which the first electrode is disposed and a second groove in which the second electrode is disposed. 19. The hollow needle of any one of claims 16 to 18, wherein the dielectric body is a cylinder having a longitudinal axis aligned with the coaxial cable, the dielectric body including a longitudinally extending channel formed therein; An electrosurgical instrument received in the longitudinally extending channel. 20. The electrosurgical instrument of claim 19, wherein the first electrode comprises a first set of longitudinally extending conductive fingers disposed about the perimeter of the dielectric body. 21. The dielectric body of claim 20, wherein the second electrode comprises a second set of longitudinally extending conductive fingers disposed about a perimeter of the dielectric body, and wherein the first and second sets of conductive fingers are disposed around the perimeter of the dielectric body. Electrosurgical instruments, characterized in that arranged in an interlocking manner. The electrosurgical instrument of any one of the preceding claims, wherein the instrument tip further comprises a shielding conductor electrically connected to the outer conductor and surrounding the electrical connection between the radiating structure and the coaxial supply cable. The electrosurgical instrument according to any one of the preceding claims, wherein one distal end of the instrument tip is formed in a smooth contoured manner to provide a pressure spot in the target area. An electrosurgical system for treating biological tissue, the system comprising:
an electrosurgical generator arranged to supply microwave energy and/or radio frequency energy; and
An electrosurgical system comprising an electrosurgical instrument according to any one of the preceding claims connected to receive microwave energy and/or radiofrequency energy from an electrosurgical generator. 25. The method of claim 24, further comprising a surgical examination device having a flexible insertion cord for insertion into the body of a patient, the flexible insertion cord having an instrument channel defined along its length, and wherein the electrosurgical instrument comprises: An electrosurgical system characterized in that the figures are formed to fit within the channel.

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